Detection of chemical agents at diluted concentrations is important for the safety of workers in certain areas such as farm workers in the field, soldiers in the field, hospital workers, chemists in production plants and the like.
One illustrative class of potentially harmful chemical agents is fumigants. Fumigants are pesticides in the form of gas that are heavier than air and have the ability to spread to all areas and surfaces. Highly volatile, fumigants are used to sterilize soil before planting crops such as potatoes, carrots and strawberries. Fumigant exposure can cause a variety of adverse health effects, ranging from simple irritation of the skin and eyes to more severe effects such as affecting the nervous system, mimicking hormones causing reproductive problems, and also causing cancer. Communities and farm workers near agricultural fields face serious risks of poisoning from drifting fumigants. The World Health Organization and the UN Environment Program estimate that each year, 3 million workers in agriculture in the developing world experience severe poisoning from pesticides, about 18,000 of whom die. Since fumigants are both toxic and gaseous, their offsite movement can pose hazardous impacts to people in nearby areas. Current quantitative measurement of the fumigants will take days and are quite costly. Thus, rapid, onsite, economic, and accurate detection and indication of exposure and concentrations of fumigants is necessary for human safety and protection of workers.